Get Window handle from point

[Sinisa]

Hi, first sorry on awkward english.

I'll try to illustrate my problem:
(dont know how will this look on your scrren)

|--Dialog----------------------------------------------------------------------------|
|
|
| |-------groupbox----
-----------------------------------------------------| |
| |
| |
| |
| |
| | |-------------------------------|
| |
| | | Button P(x,y) |
| |
| | |-------------------------------|
| |
| |
| |
| |
| |
|
|-------------------------------------------------------------------------------|
|
|
|
|
|
|-----------------------------------------------------------------------------------------|


P(x,y) represents (point) position of cursor with coordinates x,y
, and that point
lies on button.

Button and groupbox are childs from dialog.

My problem is how to get handle form Button.

i tryed something like:
(this is only part of code)

HWND hwDlg;
HWND hwGroup;
HWND hwButt;

hwGroup = :: WindowFromPoint (p);
/* this is working, i get valid handle*/

hwDlg = ::GetParent(hwG roup);
/* this is also working */

hwButt = ::RealChildWind owFromPoint(hwD lg,p);
/* but here i always get NULL */

as i understand from msdn RealChildWindow FromPoint should return child
handle if
window(in this case button) if point is "over" window , and window is
in transparent area of groupbox .

any advice is most welcome.